Documentarians Alexis Bloom and Fisher Stevens talk their moving documentary, which gains a bittersweet new meaning in the wake of Reynolds’s and Fisher’s unexpected deaths.

Alexis Bloom and Fisher Stevens began filming Debbie Reynolds and Carrie Fisher in April 2014. But gradually, their documentary Bright Lights—which premieres Saturday on HBO—evolved into something different from what they had initially imagined.

“It started with Carrie sort of wanting to pay tribute to the fact that her mother, at her age, was still putting on the gold lamé and walking onto the stage,” Bloom told VF.com Thursday about Reynolds, the Singin’ in the Rain star and MGM-era sweetheart who continued performing nightclub shows into her 80s.

“Carrie was certainly frustrated with her mother about this because she worried for her health, but she also admired her enormously. That was really the springboard for [the documentary]—Carrie thinking, ‘Wow, Mom’s still performing. Can you bloody believe it? Someone should be filming this.’”

“When we started making this film, Carrie had given us a list of people to interview—good friends and people she had worked with,” says Stevens, explaining that the film was originally meant to be a more traditional documentary—featuring people talking about Carrie and Debbie amidst archival footage. But several months into what ended up being a year and a half of filming, Stevens and Bloom realized that Debbie, Carrie, and their unique relationship—which was the subject of Fisher’s thinly-veiled roman-à-clef turned movie Postcards from the Edge—deserved more of a close-up.

“We realized that the movie was going to be more of a vérité film about Carrie and Debbie,” says Stevens. “We fell in love with these women as we got deeper and deeper in their story, and we realized that we were making a love story.”

The film captures the duo living next door to each other on a Beverly Hills compound—Fisher’s house, a zanily decorated counterpoint to her mother’s traditional home. Fisher is shown making her ailing mother meals, helping her pack for ill-advised cross-country trips, and preparing her to accept a lifetime-achievement honor. Home movies and screen footage of Fisher and Reynolds are interspersed with interviews, during which mother and daughter speak frankly about the complexity of their relationship, their love for one another, and the family’s many battles—with manic depression and drugs for Fisher, tabloid scandals and broken marriages for Reynolds. Throughout, Reynolds’s son and Fisher’s brother, Todd Fisher, cameos as a pseudo narrator, providing expert insight into the pair’s relationship.

Todd Fisher, Debbie Reynolds, Carrie Fisher

Fisher Family Archives/Courtesy of HBO.

Although the two were markedly different—Reynolds, an impeccably MGM-groomed star, and Fisher, a bawdy and brutally honest wit who described her demons in memoirs—their shared experiences bonded them in a way deeper than any romantic relationship either ever had.

“I think every woman gets older and realizes that they end up, in some ways, just like their mother,” says Bloom. Adds Stevens, “It becomes sort of an emotional echo chamber, and they had that, which was a surprise for us. We thought of them as such individual people, from such different eras. But then as we progressed with the filming, we realized how much they had in common. It took us a while, but they have a fabric that sort of unites them.”

And although Bright Lights has fabulously charming moments—of Fisher and Reynolds bantering or breaking out into spontaneous song—the filmmakers say that Fisher balked when she realized how much access she needed to provide cameras.

“As much as we adore these women, access wasn’t always guaranteed by any measure,” explains Bloom. “Carrie seems incredibly loose-talking and candid and like she lets it all hang out, but she’s actually not. She’s quite a private person. Debbie’s a private person.”

“When Carrie approached us to do this film, she didn’t really understand that we would be constantly bothering her and calling her to film,” says Stevens. “I think she thought we’d shoot a day and then make a movie. Carrie and I had so many conversations where we would say, ‘Carrie, we need to do this,’ and she says, ‘What? I’ve given you so much time.’ . . . And Debbie was much more difficult to get because Debbie really didn’t understand at the beginning what we were quite doing. Then she started to get ill, and then the access got even more difficult with her especially.”

Once Stevens and Bloom had accumulated enough footage on their own dime, they spliced together a trailer and took it to HBO, which had previously partnered with Fisher on her Wishful Drinking special. HBO not only agreed to back the project, but provided the filmmakers with behind-the-scenes footage that was taken for Wishful Drinking but never actually used—including one touching segment that shows Fisher visiting her father, Eddie Fisher, in Berkeley, California, during his final years. In the clip, the actress tells her father—who was largely absent from her childhood—how she designed her witty, wisecracking personality in an attempt to earn his affection when she was a kid. The scene is both poignant and difficult to watch—a sentiment apparently shared by Fisher when she first viewed Bright Lights.

“[Carrie] found it hard to watch the part with her father,” Stevens says. “Very hard.” Adds Bloom, “She had a strong emotional reaction to the film when she first saw it. It was more intimate than she thought it would be, and she took her time processing it. It was a number of weeks— when she watched it and re-watched it—before some things upset her less and less. . . . She sort of needed to chew it over and process her feelings and then the changes she asked for were incredibly [small]. HBO had no issue with them, and neither did we.”

Although she showed this vulnerability behind the scenes to Stevens and Bloom, she also let it slip in a few moments on-screen as well. Granted, in the documentary, Fisher is as funny as ever—cracking wise about her iconic Star Wars character and the trainer dispatched to her house by the franchise to get her back into Princess Leia shape for the spin-offs. But in between those scenes, Stevens and Bloom capture Fisher’s struggle to accept her mother’s descent into old age.

“Everything in me demands that my mother be as she always was,” Fisher says at one point in the documentary. “Even if that way is irritating. She just can’t change, and that’s the rule. . . . Age is horrible for all of us, but she falls from a greater height.”

In a twist of fate that Todd Fisher called both “horrible” and “magical,” Fisher, 60, and Reynolds, 84, died last week, within 24 hours of each other—meaning that Fisher doesn’t have to see her mother age any further, and the two will never have to be apart again. A week after that shocking turn of events, though, the documentarians are still struggling to come to grips with the fact that the bright lights they followed so closely and intimately for two years are gone.

“I’m still processing it now,” says Fisher, in the middle of back-to-back interviews for the film. “Every time I talk about [the film], I get into discussing it . . . but then, when I step out of the conversation, it’s just still so fresh and shocking and devastating. I feel really badly for Billie, Carrie’s daughter, especially, and Todd. It’s so hard on them and we just feel for the whole family more than anything.”

Remembering Carrie Fisher’s Life in Photographs

The Fisher family. From left to right: Todd, Eddie, Carrie, and Debbie Reynolds at home, 1958.

From Camera Press/Redux.

Carrie with her father, Eddie Fisher, 1959.

From Camera Press/Redux.

A mother-daughter hair moment on the set of MGM's The Mating Game, 1959.

From Mirrorpix/Everett Collection.

Reynolds with Fisher at a New York City for the School Benefit at the Town Hall, 1972.

From Getty Images.

Sixteen in New York City, 1973.

From Rex/Shutterstock.

On Warren Beatty’s shoulders on the set of Shampoo, 1975.

From Getty Images.

Hamill with Fisher on the set of Star Wars, in the 70s.

From Getty Images.

Princess Leia in Star Wars: Episode IV - A New Hope, 1977.

From Corbis/Getty Images.

From left to right: Peter Cushing, George Lucas, Fisher, and David Prowse on the set of Star Wars: Episode IV - A New Hope, 1977.

From Getty Images.

With Sissy Spacek at a New York Film Critics Circle dinner at Sardi’s in New York City, 1978.

With Princess Margaret the Star Wars premiere party at the Dorcherster Hotel in London, 1980.

From Rex/Shutterstock.

With her father Eddie, 1982.

From Getty Images.

With Mark Hamill in a scene from Star Wars: Episode VI - Return of the Jedi, 1983.

From Getty Images.

Marrying Paul Simon in New York City, 1983.

From Getty Images.

A kiss from mom Debbie Reynolds with her brother Todd at The Thalians Ball, 1985.

Time Life Pictures

With Tom Hanks filming The Burbs, 1989.

From Rex/Shutterstock.

With Meryl Streep at the premiere of Poscards from the Edge, 1990.

From Getty Images.

At Eddie Fisher's 60th birthday party with Lauren Hutton, 1998.

From Getty Images.

With Meryl Streep at the Golden Globes, 2000.

From Getty Images.

At the Britannia Awards in 2002 with Harrison Ford, Steven Spielberg, and George Lucas.

From Rex/Shutterstock.

At the Vanity Fair Oscar party, 2003.

Photographed by Jonathan Becker for the June 2003 issue.

On The Tonight Show with Jay Leno, c.2000s.

From Getty Images.

At the Emmys with Debbie Reynolds, 2011.

From Getty Images.

At the Venice International Film Festival, 2013.

From Rex/Shutterstock.

At a Marina Rinaldi launch in London with her service dog Gary.

By David M. Benett/Getty Images.

With Hamill at the Golden Hearts awards gala, 2014.

From Getty Images.

Accepting a SAG award with Reynolds, 2014.

From Getty Images.

With her daughter Billie Lourd at the Star Force: The Force Awakens premiere in Los Angeles, 2015.

From Rex/Shutterstock.

At The Force Awakens European premiere, 2015.

From Getty Images.

In New York with Gary for the Tribeca Film Festival, 2016.

Photograph by Fabrice Dall'Anese.

Alexis Bloom and Fisher Stevens began filming Debbie Reynolds and Carrie Fisher in April 2014. But gradually, their documentary Bright Lights—which premieres Saturday on HBO—evolved into something different from what they had initially imagined.

Todd Fisher, Debbie Reynolds, Carrie Fisher

Fisher Family Archives/Courtesy of HBO.

Remembering Carrie Fisher’s Life in Photographs

The Fisher family. From left to right: Todd, Eddie, Carrie, and Debbie Reynolds at home, 1958.

From Camera Press/Redux.

Carrie with her father, Eddie Fisher, 1959.

From Camera Press/Redux.

A mother-daughter hair moment on the set of MGM's The Mating Game, 1959.

From Mirrorpix/Everett Collection.

Reynolds with Fisher at a New York City for the School Benefit at the Town Hall, 1972.

From Getty Images.

Sixteen in New York City, 1973.

From Rex/Shutterstock.

On Warren Beatty’s shoulders on the set of Shampoo, 1975.

From Getty Images.

Hamill with Fisher on the set of Star Wars, in the 70s.

From Getty Images.

Princess Leia in Star Wars: Episode IV - A New Hope, 1977.

From Corbis/Getty Images.

From left to right: Peter Cushing, George Lucas, Fisher, and David Prowse on the set of Star Wars: Episode IV - A New Hope, 1977.

From Getty Images.

With Sissy Spacek at a New York Film Critics Circle dinner at Sardi’s in New York City, 1978.